Number-crunching on dog doo tells woeful tale

One of the distasteful subjects emerging from the dog ownership debate in Metro Vancouver is the issue of dog poop and the deemed failure by too many owners to clean up properly after their pets.

Poop doesn’t exactly top the list for breakfast conversation, but Sun readers responding to recent items in their morning paper about the city’s canines expressed irritation at dogs leaving unwelcome calling cards — in their gardens, on boulevards, on sidewalks, on sandy beaches frequented by children, in parks, along trails and watercourses, on playing fields and school grounds.

Dog owners stoutly protest that they do too clean up after their pets.

Precisely how much of a problem is this? Well, the evidence suggests dog poop is well on the way to becoming considerably more mountain than molehill — and not just for Vancouver.

Municipal governments everywhere now grapple with the problem of public pet excrement and dog owners who profess to clean up but don’t.

In Taiwan, one city about the size of Metro Vancouver was driven in 2009 to offer bounties ($100 T, or about $3.39 Cdn) for every kilogram of dog excrement collected and turned in. Some neighbourhoods had so much dog poop in the streets the bounty was increased to cover every half kilogram turned in.

A city in Spain made it mandatory for dog owners to register pets with a canine DNA database. Dog patrols then matched excrement found in the street or in parks to the DNA and fined delinquent owners $400 plus lab work costs.

In the United Kingdom, where cleanup costs municipal councils more than $35 million a year, concern over “dog fouling” in urban landscapes has reached the point that in some regions closed circuit television surveillance is being used to nab offenders. Work in the U.K. is even afoot to profile dog poop outlaws. So far, it seems, distinguishing socio-economic characteristics are absent but offending owners tend to be younger and, slightly more often, male.

Authorities in Northern Ireland, where mandatory canine microchips are already the rule, have also been debating whether to adopt the Spanish city’s lead and use DNA testing to trace and prosecute dog poop scofflaws. Similar initiatives are gaining traction with municipal governments in Germany, Israel and the U.S.

Dog poop and what to do about it — and about the dog owners responsible for their pets’ dirty business — has recently been the subject of scientific research, waste management studies by governments and articles in mainstream popular science magazines like Psychology Today.

There’s now a whole sub-industry of dog poop management contractors out there.

So, what about Vancouver?

First off, nobody knows precisely how many dogs populate the high-density urban landscape. However, if estimates of 145,000 dogs are correct, then applying University of B.C. scholar Stanley Coren’s approximation (published in a recent Psychology Today article) of an average production of about 340 grams of fecal matter per dog per day, simple arithmetic indicates man’s best friend must deposit about 50 tonnes of excrement on the city every 24 hours.

Over a year that totals about 18,000 tonnes — more than 1.5 times the weight of BC Ferries’ biggest ship.

It gets more interesting. Across Metro, applying the mathematical formula developed for calculating urban dog populations by the U.S.-based National Council for Pet Population Study and Policy, there should be an estimated 500,000 pet dogs. These canines would produce about 167 tonnes of excrement every 24 hours — or 61,000 tonnes a year, equal to five BC Ferries the size of the Spirit of Vancouver Island.

And that’s just the solid waste. On average, dogs produce about .75 litres of urine every day, too, which means that across Metro Vancouver they pee enough to fill 55 Olympic-size swimming pools each year.

Much of that poop first goes on the ground, leaving residues behind even where responsible dog owners collect the fecal matter afterward. Almost all the urine is deposited there but is not cleaned up because there’s no practical way to do so.

That means more than 100,000 litres of dog urine a day, equivalent to about nine standard-sized septic tank truck loads, soaks into Vancouver’s lawns, gardens, parks, playgrounds and runs off into storm drains and waterways.

Even dog excrement collected by responsible owners poses a growing problem. While human waste almost exclusively goes into sewers for proper treatment at the region’s five facilities, a significant amount of pet waste goes into the garbage and ultimately into landfills despite bylaw prohibitions. Large quantities of fecal matter entering landfills are cause for concern for several reasons:

• First, there are potential health hazards to municipal waste workers from the bacteria, viruses and parasites in the excrement they collect and transport.

• Second, there’s the potential for contamination of soils and waterways should the fecal matter leach into the water table.

• Third, decomposing pet waste is a source of methane emissions.

• Fourth, pet waste is usually dumped in the trash in non-biodegradable plastic bags, which hinders the composting process.

Toronto did a city-wide waste audit in 2006 and discovered park litter bins contain up to 27 per cent dog waste by weight. A followup audit in 2008 found despite educational campaigns, pet waste still comprised up to 26 per cent of the park litter bin contents by weight.

Audits in Colorado found 60 per cent of urban dog waste — approximately 30,000 tonnes — went into trash receptacles while 40 per cent, or 20,000 tonnes, was left on the ground by dog owners.

In Vancouver, disposal of any excrement in garbage containers is prohibited by law and dog owners are urged to flush dog waste down the toilet. However, there’s tacit acknowledgment that a lot of this excrement goes into household garbage and public trash receptacles, so officials admit that out of practicality they must turn a blind eye except for egregious quantities.

Hardly surprising then that Metro Vancouver’s solid waste managers confirm that an audit of the solid waste stream in 2010 identified 16,553 tonnes of pet waste present when it was legally not supposed to be contaminating the region’s municipal garbage.

Research indicates that many dog owners who don’t bother to pick up and dispose of their dog’s excrement fail to do so in the mistaken belief that it’s a benign, if messy, biodegradable substance that will simply go away over time. They are mistaken.

“Dog waste is not fertilizer, it’s full of bacteria, nitrogen and salts which don’t dissolve and can be very harmful to plants, aquatic life and humans. Dog feces can also carry pathogens,” warns a Vancouver municipal advisory to dog owners. “As many of the trails and park areas are used as outdoor classrooms for children, it’s important to clean up after your pet.”

So aside from the esthetic issues of nasty dog excrement on sidewalks and lawns and the unpleasant inconvenience of cleaning it off your shoe after stepping in it, there are significant associated public health concerns. Among the human diseases transmitted by exposure to dog poop are:

• Campylobacter: symptoms of infection include diarrhea, abdominal pain, and fever and last about a week, although in people with suppressed or compromised immune systems there can be life-endangering infections of the bloodstream.

• E. coli: fecal coliform infections are among the most infamous as a result of fatal contamination of municipal water supplies from animal waste in recent years. Infection results in stomach pain, nausea, vomiting, diarrhea and fever, while some variants can cause lethal kidney failure. It, too, places both people with compromised immune systems and young children at particular risk.

• Salmonella: symptoms include muscle aches, headache, vomiting, diarrhea and fever. This is the most common bacterial infection transmitted from animals to humans.

• Yersiniosis: the bacteria responsible causes intestinal infections and, unlike other organisms, thrives in cold water, which means it multiplies in ponds, puddles and lakes as ice and snow melt in the spring. Dog feces covered by snow for the winter can therefore contaminate bodies of water long after being deposited.

• Cyclospora, Cryptosporidium and Giardia: these parasites pass from dog feces and contaminate fresh water. They result in intestinal infections that usually pass in adults but can be accompanied by severe abdominal pain and bloody diarrhea.

• Parasitic worms: dog feces carry eggs that can lie dormant in contaminated soil for up to two years, even with repeated freezing. Tapeworms invade the digestive tract. Various roundworm larvae hatch in the bloodstream and can cause serious debilitating conditions. Small children who often go barefoot and who frequently touch their faces and put things in their mouths are at particular risk.

One British report on dog fouling found that 54 per cent of dog owners had neither bought nor used worming tablets on their pets and a random sampling of parks in the U.K. found many contaminated. A Canadian study in 2007 surveyed veterinarians in Western Canada and concluded that deworming protocols are often ineffective in preventing pets from shedding parasites with feces.

Toxocara is one roundworm found in dog feces worldwide. A 2008 study of feces from animal shelters in Ontario and Quebec found 34 per cent had intestinal parasites including roundworms. A random study of 332 dogs in Montreal found 34 per cent were infected. A dog’s single bowel movement can deposit a million toxocara eggs. Human infection with this parasite is called toxocariasis. Epidemiologists believe the disease is underdiagnosed and the U.S. CDC says it’s considered a “neglected parasitic infection” that’s poorly understood by health care providers.

The BC Centre for Disease Control says no human cases of toxocariasis have ever been reported in this province, although one small study of Canadian children elsewhere found 17 per cent had antibodies that showed exposure.

Outbreaks in B.C. of the other diseases listed have been associated with pets, most often in young children.

The Canadian Public Health Association reports that bacteria counts in urban waterways rise following rain and cites recent studies in the U.S. that traced bacteria from urban watersheds back to dog excrement. Bacterial source tracking in Seattle linked 20 per cent to dogs and concluded that a few days of droppings from 100 dogs would contribute enough contaminants to close a typical bay to swimming or shellfish harvests.

So the subject of dogs defecating in parks, school grounds, on playing fields, picnic areas, near children’s playgrounds or sharing sandy beaches with human and young children raises health concerns. “It is a really important public health issue,” says Dr. Bonnie Henry of the BCCDC.

Salmonella, campylobacter, cryptosporidium and E. coli outbreaks in B.C. have all been associated with pets, she said. Of the diseases the CPHA directly associates with pet feces, B.C. has had more than 32,000 cases reported over the decade between 2000 and 2009. BCCDC reports show 16,601 cases of Campylobacteriosis; 6,825 cases of Yersiniosis; 6,650 cases of Giardiasis; 1,489 cases of a toxic E. coli infection and 1,174 cases of Cryptosporidiosis.

Highest rates of infection for all these diseases in B.C. occur in Metro Vancouver.

While infections can certainly be contracted from wildlife-contaminated water while hiking or camping, the highest rates of infection for all these diseases, including giardiasis, occur among B.C. children under nine, with particularly heavy concentrations under age five, which suggests other sources of exposure than hiking.

What’s the solution?

First, lots of hand washing, says Henry, particularly for children in households with pets and when playing outdoors where they might come into contact with contaminated sand, soil or water. If outdoors, take alcohol-based hand rub or alcohol-based baby wipes along and use them prolifically and always after cleanup and disposal of dog feces.

Second, educating dog owners about the extent of the problem and instilling a sense of responsibility in those who don’t demonstrate an understanding of their civic duty.

Strictly segregating — perhaps with fencing — areas where dogs can roam off leash from areas used by other members of the public, particularly small children, would seem prudent. (Some dog-owning readers even suggest establishing separate play areas for large and small dogs to minimize injury in case of conflict.)

Developing an aggressive region-wide collection and composting system to separate all pet waste from the garbage stream — perhaps funded in part by reasonable fees levied upon owners (let’s please keep the substantial public benefits of dog ownership in mind here) — might be another.

Asking dog owners for their ideas about how to reasonably reconcile their needs, their dogs’ needs and the desires of the non-dog-owning majority would be a good thing, too.

In any event, there appears to plenty to discuss and this is a civil conversation we urgently need to have, sooner, rather than later. Why is it urgent? Because, if growth projections for regional population and pet ownership are accurate, there’s a tsunami of dog poop, more than a million tonnes of it, headed our way over the next 20 years.

And when it comes to the arrival in town of a million tonnes of dog poop, the old planning adage that you can either manage change or the change will manage you takes on a certain compelling fascination.

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